In order to understand how modern citizens think and feel about politics, we need to understand what their political minds were designed for. There is only one explanation for functional biological design: evolution by natural selection. In this talk, I will discuss and illustrate how evolution designed the human mind to help our ancestors navigate in the politics of small-scale groups and how this design of the political mind continues to shape modern politics. Perhaps surprisingly, much irrationality in modern politics is a direct consequence of a mind that is extremely well-designed for the politics of the past.